https://www.usatoday.com/story/news/world/2018/02/20/mexican-cartels-switch-gears-after-u-s-states-relax-u-s-states-legalize-marijuana-mexicos-cartels-sw/343389002/

"..small farmers, or campesinos, in this border state's rugged Sierra Madre who long planted marijuana to be smuggled into the United States are switching to opium poppies, which bring a higher price. The opium gum harvested is processed into heroin to feed the ravaging U.S. opioid crisis.

“Marijuana isn’t as valuable, so they switched to a more profitable product,” said Javier Ávila, a Jesuit priest in this region rife with drug cartel activities.

Laws allowing marijuana in states like Colorado, Washington and California are causing shifts in the Mexican underworld that have also led to increased violence as the cartels move away from its cash cow of marijuana to traffic more heroin and methamphetamines.."

This is usually coupled with a 'culture' of rock stars who claim junkiedom, like you saw in the 90s when the Black Tar Mexican Heroin was coming in heavily from South of the Border.